From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794311499; b=Ytecdh0OgGzl/+sh1zR5nFDgAGc5Jdcbdkvxoq5H9kW6NGbf1gehfJKxKo1yOUFte8O5 677Fp0UDuhXKCiFIY+n2h/x96XFZW8KHAcvGGwhRVqAhBQctOYx8RhRtd09CHuZf2pWX8 HwHrS+R+yfPRYHAICL9WwBokiX/PUnwbt43p3Zk/kHl0bE0nLdJ898WlGQU6hZiXtEtc8 0Muxm7+XWuFy6pRNlgDiyTvPISIWwPPaXrmJUOjFJoggq3o0uL/tR+XaGxKs4WaeP+vYn Pq8pMgmPKis46aLLLuO/9crWdrmH/Jg/aOclgDJky9GWwcx9Snh2ODgjNFuBC/vXW/w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794311499; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=bdcJHbcMqJuwQrgxqKJoVDct8dTsY2WZV2zQTS/1CKI=; b=HfudXJgPdYA6q48z1mKHmes5uIsr8qJjwIvjmBvTDJJFlq1jSw6mZMyaif3T3HXy36Ue Ah93BNUvTSFpLZ8S+9Wtx1jmBPEcm7sTS8BYUWk5f4QWMbbGHqK5NuKx/E2sJXw/k+cUw uwuRPWKzYoBgFBgatcBzF5xq9JbtLxgRNZ7N0ljv94+AcgdwgSyC/G6a6KlwWR1rng8Te 9/tUCLSaTVLHUlv/YGEGyOaoPITF8E5Pg7SpKDXimf42/8apWbkuvlYe7fbDje1aQl3ZD 4Db8K3gE1oQyCyPviU0UYeydCNDqsoJCZQIWF20FkaPOHsTvy2lvQJ1iGWeZ5syQC0A== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=ZFoM2RqL; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F1CD860A383D for ; Tue, 10 Nov 2026 11:51:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=ZFoM2RqL Received: by smtp.kernel.org (Postfix) with ESMTPSA id A7C961F0089F; Tue, 10 Nov 2026 11:51:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794311498; bh=bdcJHbcMqJuwQrgxqKJoVDct8dTsY2WZV2zQTS/1CKI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ZFoM2RqLvU9431g2RumK9tilWDrR2HacSU7puXf0YiaSNAcfrT9vOeXA3y2ZEKOyw 7xVlfnhlw0p3xzkWAUduez8CzoKgXtfmYjYTH2r465vyAvrneuyBAhThWNWgRjcso7 9GGphM9d8Dd4VRO5SG89Am0RjMBH/6IrMNMlgFZRmX5XOc/pG3Wp1EEmAfwfpUMQbp Z0n9W+K7Al1QxYrnp+DrL4z8KSGwMBd3zNtxhHEm2vyfvUHLOJVYLmgRI0JzzWR0YK P7rw/9EcBzBJMgLeoSKgVkatkUxdkEd3/I6Ztwk02IRXa2oVE2TAwVLqM2ExWmzi5M WTa2mYsH0aMWw== From: Sasha Levin To: stable@vger.kernel.org Cc: David Hildenbrand , Zi Yan , SeongJae Park , Wei Yang , Lorenzo Stoakes , "Liam R. Howlett" , Andrew Morton , Sasha Levin Subject: [PATCH 6.12.y 1/2] mm/page_alloc: reject unreasonable folio/compound page sizes in alloc_contig_range_noprof() Date: Tue, 10 Nov 2026 06:51:35 -0500 Message-ID: <20261110115129.609167-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261107051925-failed-6.12-4c767c5dd9bc@kernel.org> References: <20261107051925-failed-6.12-4c767c5dd9bc@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: David Hildenbrand [ Upstream commit 0bf2edf041dcb0b304a8dbda8c699771d5a245d2 ] Let's reject them early, which in turn makes folio_alloc_gigantic() reject them properly. To avoid converting from order to nr_pages, let's just add MAX_FOLIO_ORDER and calculate MAX_FOLIO_NR_PAGES based on that. While at it, let's just make the order a "const unsigned order". Link: https://lkml.kernel.org/r/20250901150359.867252-7-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Zi Yan Acked-by: SeongJae Park Reviewed-by: Wei Yang Reviewed-by: Lorenzo Stoakes Reviewed-by: Liam R. Howlett Signed-off-by: Andrew Morton Stable-dep-of: 4c767c5dd9bc ("mm/page_isolation: guard compound_order() against racing") Signed-off-by: Sasha Levin --- include/linux/mm.h | 6 ++++-- mm/page_alloc.c | 10 +++++++++- 2 files changed, 13 insertions(+), 3 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 1728dc3356089..f05962963e28d 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2058,11 +2058,13 @@ static inline long folio_nr_pages(const struct folio *folio) /* Only hugetlbfs can allocate folios larger than MAX_ORDER */ #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE -#define MAX_FOLIO_NR_PAGES (1UL << PUD_ORDER) +#define MAX_FOLIO_ORDER PUD_ORDER #else -#define MAX_FOLIO_NR_PAGES MAX_ORDER_NR_PAGES +#define MAX_FOLIO_ORDER MAX_PAGE_ORDER #endif +#define MAX_FOLIO_NR_PAGES (1UL << MAX_FOLIO_ORDER) + /* * compound_nr() returns the number of pages in this potentially compound * page. compound_nr() can be called on a tail page, and is defined to diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 480579d7d59e4..887dd3f06a86b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6685,6 +6685,7 @@ static int __alloc_contig_verify_gfp_mask(gfp_t gfp_mask, gfp_t *gfp_cc_mask) int alloc_contig_range_noprof(unsigned long start, unsigned long end, unsigned migratetype, gfp_t gfp_mask) { + const unsigned int order = ilog2(end - start); unsigned long outer_start, outer_end; int ret = 0; @@ -6699,6 +6700,14 @@ int alloc_contig_range_noprof(unsigned long start, unsigned long end, }; INIT_LIST_HEAD(&cc.migratepages); + /* + * In contrast to the buddy, we allow for orders here that exceed + * MAX_PAGE_ORDER, so we must manually make sure that we are not + * exceeding the maximum folio order. + */ + if (WARN_ON_ONCE((gfp_mask & __GFP_COMP) && order > MAX_FOLIO_ORDER)) + return -EINVAL; + gfp_mask = current_gfp_context(gfp_mask); if (__alloc_contig_verify_gfp_mask(gfp_mask, (gfp_t *)&cc.gfp_mask)) return -EINVAL; @@ -6786,7 +6795,6 @@ int alloc_contig_range_noprof(unsigned long start, unsigned long end, free_contig_range(end, outer_end - end); } else if (start == outer_start && end == outer_end && is_power_of_2(end - start)) { struct page *head = pfn_to_page(start); - int order = ilog2(end - start); check_new_pages(head, order); prep_new_page(head, order, gfp_mask, 0); -- 2.53.0